The sphygmomanometer disclosed in JP 2008-148765A (Patent Document 1) includes a cuff unit serving as a measurement unit, and a base on which the elbow of an arm is placed after having passed through the cuff unit. The cuff unit is attached to the base such that its inclination angle relative to the horizontal plane can be changed.
An elbow detection mechanism for detecting the placement of an elbow is provided at a predetermined position on the base. The sphygmomanometer can measure the blood pressure of a measurement subject when the elbow detection mechanism has detected the placement of an elbow. However, even if the elbow of the measurement subject has passed through the cuff unit, the sphygmomanometer does not measure the blood pressure of the measurement subject if the elbow detection mechanism has not detected the placement of the elbow.
Consideration will now be given to the inclination angle of the cuff unit relative to the base, based on differences in the physiques of measurement subjects. If the measurement subject has a small physique, the position of their shoulders is lower than that of a measurement subject who has a large physique. For this reason, if their elbows are placed on the same horizontal plane, the inclination angle of the upper arm tends to be steep for a measurement subject who has a large physique and gentle for a measurement subject who has a small physique.
When an upper arm is inserted into the cuff unit of a sphygmomanometer having the above configuration, it is often the case that the inclination angle of the cuff unit relative to the base is larger if the measurement subject has a large physique, and that the inclination angle of the cuff unit relative to the base is smaller if the measurement subject has a small physique.
The elbow detection mechanism of the above-described sphygmomanometer is provided fixed at a predetermined position on the base, and a mechanism for changing the inclination angle of the cuff unit relative to the base is provided on the lower end side of the cuff unit. Consequently, the smaller the inclination angle of the cuff unit is, the greater the distance between the entrance of the cuff unit and the elbow detection mechanism is. For this reason, the distance to the elbow detection mechanism is longer for the measurement subject whose physique is small, regardless of the fact that the length of their upper arm is shorter than that of a measurement subject whose physique is large, and it is possible that this will be a cause for loss of an appropriate measurement posture.
Examples of other sphygmomanometers that include an elbow detection mechanism are disclosed in JP 3001683U (Patent Document 2) and JP H11-342117A (Patent Document 3). Also, another sphygmomanometer that includes an elbow holder is disclosed in JP 2005-334125A (Patent Document 4).